Antibiotics for Cat Bite Injuries

(CATBITE Trial)

Recruiting in Palo Alto (17 mi)

Overseen by Kevin M Klifto, DO, PharmD

Age: 18+

Sex: Any

Travel: May Be Covered

Time Reimbursement: Varies

Trial Phase: Phase 4

Recruiting

Sponsor: University of Missouri-Columbia

Must not be taking: Corticosteroids, Calcineurin inhibitors

Disqualifiers: Immunocompromised, Diabetes, Malignancy, others

Prior Safety Data

Approved in 3 Jurisdictions

Trial Summary

What is the purpose of this trial?

Cat bites are puncture wounds that have the potential to seed bacteria deep within the joint capsule, periosteum, and bone. The hand is the most common site of bite injuries. Pasteurella multocida is the is the most common organism isolated from the mouths of cats that can cause infections after a bite. Prophylactic antibiotics are often recommended with amoxicillin-clavulanate for 3-5 days to decrease the incidence of developing an infection. However, only one randomized controlled clinical trial consisting of 12 patients has been performed to justify this course of treatment, raising the possibility that the use of antibiotics could be reduced or even eliminated. Investigators will compare different durations of prophylactic antibiotics and a placebo control for cat bites to the hand/forearm presenting to the Emergency Department, Urgent Care, Plastic Surgery Clinic using a randomized, controlled, double-blind clinical trial. Participants presenting to the University of Missouri Hospital Emergency Department, Missouri University (MU) Healthcare Urgent Care, Plastic Surgery Clinic over the next year will be offered the chance to enroll if they meet the inclusion/exclusion criteria. For inclusion, participants will be \>18 years of age, have cat bites to the hand or distal to elbow, and present within 24 hours of the cat bite injury. Participants must not present with active local or systemic infections, have received antibiotics within the past 30 days, or be immunocompromised (primary and secondary immunodeficiencies). Participants will be randomized to one of three treatment arms (placebo; amoxicillin-clavulanate 1 day; amoxicillin-clavulanate 5 days). Outcomes are the development of an infection at the location of the cat bite and/or systemic infection, adverse effects of interventions, disability assessed by Quick Disabilities of Arm, Shoulder and Hand (QuickDASH) scores, and quality of life (QOL) assessed by HAND Questionnaire (HAND-Q) scores. Infection will be assessed at day 0, day 2, day 7+/-2, day 14+/-2, and day 30+/-2 by vital signs, laboratory values, physical examination and with an infrared and digital camera. All measures will be within the standard of care, apart from the infrared camera, QuickDASH, and HAND-Q scores. The anatomic locations of cat bites to the hand/forearm will be assessed for correlations with infections.

Do I need to stop my current medications to join the trial?

The trial does not specify if you need to stop taking your current medications. However, if you have taken antibiotics in the past 30 days or are on immunosuppressive drugs, you may not be eligible to participate.

What data supports the effectiveness of the drug Amoxicillin/clavulanate for cat bite injuries?

Research shows that Amoxicillin/clavulanate is effective in reducing infection rates in animal bite wounds that are 9-24 hours old. It is also the most active antibiotic against the bacteria commonly responsible for infections from cat bites. ^{1 2 3 4 5}

Is amoxicillin/clavulanate safe for treating cat bite injuries?

Amoxicillin/clavulanate is generally safe for humans, but it can cause side effects like loose stools or diarrhea. It is often used to prevent infections from cat bites, especially in wounds that are 9-24 hours old. ^{1 2 3 6 7}

How does the drug amoxicillin/clavulanate differ from other treatments for cat bite injuries?

Amoxicillin/clavulanate is unique because it combines a broad-spectrum antibiotic with a beta-lactamase inhibitor, making it effective against a wide range of bacteria, including those commonly found in cat bites. It is particularly recommended for wounds that are 9-24 hours old, where it significantly reduces infection rates, unlike other treatments that may not be as effective in this time frame. ^{1 2 3 4 8}

Research Team

Kevin M Klifto, DO, PharmD

Principal Investigator

University of Missouri-Columbia

Eligibility Criteria

Adults over 18 who've been bitten by a cat on the hand or forearm within the last 24 hours can join this trial. They must speak English and be willing to take medication and attend follow-ups. Excluded are those with active infections, recent antibiotic use, immunodeficiencies, certain chronic diseases, fever above 100.4°F, pregnancy, malnutrition or hypersensitivity to study drugs.

Inclusion Criteria

I am 18 years old or older.

Bitten by a cat

I was bitten by a cat on my hand or forearm less than 24 hours ago.

Exclusion Criteria

I currently have an active infection.

I have redness and swelling where a cat bit me.

I currently have a fever higher than 100.4° F.

Trial Timeline

Screening

Participants are screened for eligibility to participate in the trial

1 week

1 visit (in-person)

Treatment

Participants receive either placebo or amoxicillin-clavulanate for 1 or 5 days

1-5 days

Day 0, Day 2

Follow-up

Participants are monitored for infection development and adverse effects

4 weeks

Day 7, Day 14, Day 30

Outcome Assessment

Assessment of QuickDASH and HAND-Q scores to evaluate disability and quality of life

4 weeks

Day 30

Treatment Details

Interventions

• Amoxicillin/clavulanate (Antibiotic)
• Placebo (microcrystalline cellulose) (Other)

Trial Overview The CATBITE trial is testing if antibiotics prevent infection after a cat bite to the hand/forearm. Participants will randomly receive either a placebo; amoxicillin-clavulanate for one day; or amoxicillin-clavulanate for five days. The study will monitor infection development and assess disability and quality of life through questionnaires.

Participant Groups

Group I: Antibiotic x 1 day Active Control 5 Interventions

Amoxicillin-clavulanate 875-125mg capsules by mouth twice daily x 1 day (4 days of placebo capsules) -Penicillin allergy: ciprofloxacin 500mg by mouth twice daily + clindamycin 300mg by mouth three times daily x 1 day

Group II: Antibiotic x 5 days Active Control 4 Interventions

Amoxicillin-clavulanate 875-125mg capsules by mouth twice daily x 5 days (0 days of placebo capsules) -Penicillin allergy: ciprofloxacin 500mg by mouth twice daily + clindamycin 300mg by mouth three times daily x 5 days

Group III: Placebo (microcrystalline cellulose) Placebo Group 2 Interventions

Placebo capsules by mouth twice daily x 5 days (5 days of placebo microcrystalline cellulose capsules)

Amoxicillin/clavulanate is already approved in Canada for the following indications:

Approved in Canada as Clavamox for:

• Bacterial infections
• Respiratory tract infections
• Skin and soft tissue infections
• Urinary tract infections

Who Is Running the Clinical Trial?

University of Missouri-Columbia

Lead Sponsor

Trials

387

Recruited

629,000+

Mun Y. Choi

University of Missouri-Columbia

Chief Executive Officer since 2017

PhD in Mechanical and Aerospace Engineering from Princeton University

Richard Barohn

University of Missouri-Columbia

Chief Medical Officer since 2020

MD from the University of Missouri-Columbia School of Medicine

Findings from Research

In a study of 185 patients with full thickness animal bite wounds, prophylactic antibiotics (amoxycillin/clavulanate) showed no significant benefit for wounds less than 9 hours old.

For wounds aged 9-24 hours, the use of antibiotics significantly reduced the infection rate, suggesting they are beneficial in this time frame, while their use in newer injuries is questioned unless deeper structures like tendons or joints are involved.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A comparative double blind study of amoxycillin/clavulanate vs placebo in the prevention of infection after animal bites. Brakenbury, PH., Muwanga, C.[2019]

In the Netherlands, animal bites lead to significant infections, particularly from Pasteurella multocida, which can cause serious complications, as seen in three reported cases of wound healing disturbances.

For cat bites, a 5-day course of amoxicillin/clavulanic acid (Augmentin) is recommended as prophylaxis due to the high infection risk, while the necessity of prophylaxis for dog bites is debated, especially considering potential severe infections from Capnocytophaga canimorsus.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Pasteurella multocida infections: bites by dogs or cats?]. Tjong Joe Wai, R., van Zeijl, JH.[2006]

Infections are the most common complication from animal bites in children, and the choice of antibiotic therapy should be tailored based on individual risk factors such as the type and location of the bite, and the patient's health status.

For most bacterial infections resulting from bites, the combination of amoxicillin and clavulanic acid is the most effective treatment, and it should be started quickly and continued for 3-5 days while monitoring for local symptoms.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

[Antibiotic prophylaxis for bites in children]. Quinet, B., Grimprel, E.[2013]

Dog bites, especially in children, are common and often lead to infections caused by bacteria such as Pasteurella multocida and Staphylococcus aureus, necessitating antibiotic treatment for both infected and at-risk wounds.

Effective management of bite wounds includes not only antibiotics like amoxicillin-clavulanate but also proper wound care through irrigation and debridement, with surgical repair being the preferred method for uninfected facial wounds.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Facial bite wounds: management update. Stefanopoulos, PK., Tarantzopoulou, AD.[2005]

Exotic pet-related injuries, such as those from parrot bites, require special attention due to the unique pathogens they can transmit, which are not adequately covered by standard antibiotics like amoxicillin/clavulanic acid.

A case report highlights the need for thorough microbiological assessment in managing injuries from exotic pets, emphasizing that typical treatment protocols may not be sufficient for these types of wounds.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Managing parrot bite injuries to the hand: not just another animal bite. King, IC., Freeman, H., Wokes, JE.[2018]

Clavulanate-potentiated amoxycillin significantly improved the resolution of skin lesions in dogs compared to amoxycillin alone, with faster healing observed in experimental infections (P < 0.05).

In clinical cases, dogs and cats treated with clavulanate-potentiated amoxycillin required a shorter treatment duration and had a higher success rate, particularly against amoxycillin-resistant infections (P < 0.01).

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Efficacy of clavulanate-potentiated amoxycillin in experimental and clinical skin infections. Bywater, RJ., Hewett, GR., Marshall, AB., et al.[2019]

References

1. England pubmed.ncbi.nlm.nih.gov

A comparative double blind study of amoxycillin/clavulanate vs placebo in the prevention of infection after animal bites. [2019]

2. Netherlands pubmed.ncbi.nlm.nih.gov

[Pasteurella multocida infections: bites by dogs or cats?]. [2006]

3. France pubmed.ncbi.nlm.nih.gov

[Antibiotic prophylaxis for bites in children]. [2013]

4. Denmark pubmed.ncbi.nlm.nih.gov

Facial bite wounds: management update. [2005]

5. United States pubmed.ncbi.nlm.nih.gov

Managing parrot bite injuries to the hand: not just another animal bite. [2018]

6. England pubmed.ncbi.nlm.nih.gov

Outpatient therapy of bite wounds. Demographic data, bacteriology, and a prospective, randomized trial of amoxicillin/clavulanic acid versus penicillin +/- dicloxacillin. [2019]

7. England pubmed.ncbi.nlm.nih.gov

Efficacy of clavulanate-potentiated amoxycillin in experimental and clinical skin infections. [2019]

8. England pubmed.ncbi.nlm.nih.gov

Pharmacokinetics of the amoxicillin-clavulanic acid combination after intravenous and oral administration in cats. [2020]